The other answers on this page are great. One small recommendation would be to add /usr/lib/oracle/11.2/client64/lib in a new file under the /etc/ld.so.conf.d/ path. Then you don't need to set LD_LIBRARY_PATH, see also here.
– Elliott FrischFeb 28 '14 at 18:19

csh or tcsh

If you want to make it permanent for all users, you can edit the corresponding files under /etc/, i.e. /etc/profile for Bourne-like shells, /etc/csh.login for (t)csh, and /etc/zsh/zprofile and /etc/zsh/zshrc for zsh.

Another option is to use /etc/environment, which on Linux systems is read by the PAM module pam_env and supports only simple assignments, not shell-style expansions. (See Debian's guide on this.)

These files are likely to already contain some assignments, so follow the syntax you see already present in your file.

Make sure to restart the shell and relogin the user, to apply the changes.

If you need to add system wide environment variable, there's now /etc/profile.d folder that contains sh script to initialize variable.
You could place your sh script with all you exported variables here.
Be carefull though this should not be use as a standard way of adding variable to env on Debian.

@user3021349 I don't meant to be rude but if you think one second you can also use a different editor you master. :wq is the command to write file and exit in vi don't forget to type esc before
– KiwyFeb 28 '14 at 13:59

3

You'll need to consider the environment variables in crontab scripts. None of these locations will be looked up when a crontab script is running.
– yegleMar 1 '14 at 1:04

To do if for all users/shells, depending on distro you could use /etc/environment or /etc/profile. Creating a new file in /etc/profile.d may be preferable if it exists, as it will be less likely to conflict with updates made by the packaging system.

In /etc/environment, variables are usually set with name=value, eg:

ORACLE_HOME=/usr/lib/oracle/11.2/client64

In /etc/profile, you must use export since this is a script, eg:

export ORACLE_HOME=/usr/lib/oracle/11.2/client64

Same goes for a file under /etc/profile.d, there also may be naming restrictions which must be met for the file to work. On Debian, the file must have the extension .sh (although does not need a bang line or executable permissions since it is sourced). check your distro documentation or look at the /etc/profile script to see how these files are loaded.

Note also though that setting LD_LIBRARY_PATH permanently is potentially problematic, including being a security risk. As an alternative, I would suggest finding some way to prepend the LD_LIBRARY_PATH to the start of the command line for each program that needs it before running. Eg:

LD_LIBRARY_PATH=/usr/lib/oracle/11.2/client64/lib myprog

One way to do this is to use a wrapper script to run the program. You could give this the same name as your program and put it in /usr/local/bin or anywhere that appears before the location of your program in PATH. Here is an example script (don't forget to chmod +x the script):

so, if I've added value pairs to my environment file, what causes those to load up? For example, after exiting vi editor (changes written successfully) , I'm expecting to write echo $MY_NEW_VARIABLE and see it print out - EDIT: I see they're there if I launch a new command shell
– bkwdesignJan 22 '16 at 0:28

Unsure if this is a personal issue or what, but I had to reboot my OS after setting this in /etc/environment, even if I restarted the bash terminal or typed source /etc/environment. So if you're having issues where the environment variable isn't perpetuating, try rebooting.
– Blairg23Jan 11 '18 at 1:04

@bkwdesign @Blairg23, /etc/environment is not a script, so it cannot be sourced. It's loaded at login time (and a handful of other system events) by PAM, so you can either logout/login or run a new login session in a terminal by $ su <your username here> to pick up the new values in that isolated session. The values will disappear once you exit, so it's probably less error-prone to just fully logout/login.
– AaronDanielsonFeb 12 '18 at 18:33

when you install oracle, oracle asked that you run some scripts before clicking ok. That script put a dummy setting in the .bash_profile in oracle user home directory. To see the file, ls -al will show all hidden files.

type nano bash_profile to open the file. Make changes to the file to reflect your hostname, and appropriate sid name. check any other settings that need modification. press control x to save and type y when asked if you want to save. Press the return key to save.
Restart the computer. Logging as oracle user. start the database by typing

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